Hydrogenation processes for the upgrading of heavy cretaceons crude oil and bitumens are well known. Upgrading processes are normally carried out to remove or reduce the contaminants in the oil and to convert the heavier components of the oil into lower boiling point hydrocarbon products. The contaminants include the heteroatoms oxygen, sulphur and nitrogen and the metals vanadium, nickel and iron.
Current commercial upgrading processes typically involve the use of a heterogeneous catalyst, exemplary of which would be cobalt, molybdenum or nickel sulfides deposited on an alumina substrate. Deleteriously, the higher molecular weight components of the heavy oils tend to accumulate on the catalyst pellet surfaces, clogging the pore system and thus reducing the rate of hydrogenation. Ultimately, the deposition of coke and metals on the pellet surface will despoil the catalytic performance. This becomes a serious operational problem when feedstocks such as bitumen, which are high in asphaltenes are hydrocracked.
The types of reactor employed in hydrocracking processes typically comprise a tubular reactor containing a fixed bed of the catalysts mentioned supra, or a fluidized bed of catalyst. Recovery of spent catalyst, and indeed replacement thereof, is a major expenditure in the process.
Typical hydrocracking reaction conditions are undertaken at high temperatures, of the order of between 400.degree.-840.degree. C. and at high pressures namely about 2,000-3,000 psi or higher.
It would be desirable, therefore, if a process not requiring a solid catalyst and requiring less severe reaction conditions could be arrived at.